PIC16F636-I/P - 8-bit Flash MCU, 3.5KB, KeeLoq, DIP-14 | Microchip
MPN: PIC16F636-I/P ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.37 | $2.37 |
| 10 | $2.15 | $21.50 |
| 100 | $1.92 | $192.00 |
| 500 | $1.74 | $870.00 |
| 1,000 | $1.58 | $1,580.00 |
PIC16F636-I/P Overview
An 8-bit microcontroller (MCU) is a single-chip computer built around an 8-bit data path that integrates a CPU, RAM, non-volatile program memory, peripherals and I/O on one die. The PIC16F family uses Microchip's Harvard RISC architecture, sitting in the broader hierarchy of microcontroller -> embedded processor -> semiconductor IC, and is widely used in cost-sensitive embedded applications where deterministic timing and low power are priorities.
Key features of this part include 12 I/O pins, two analog comparators, a programmable Low-Voltage Detect (PLVD) module, an internal 8 MHz oscillator, an ICD (In-Circuit Debug) interface, and a KeeLoq-compatible hardware Cryptographic Module for secure rolling-code applications such as remote keyless entry. The device is supported by Microchip's MPLAB X IDE, XC8 compiler, and PICkit programmers, and offers 35 single-word instructions to minimize learning curve.
The PIC16F636 integrates an 8-bit ALU with a 14-bit instruction word, an instruction pipeline, hardware interrupt controller, brown-out reset, power-on reset, watchdog timer with its own on-chip RC oscillator, and on-chip EEPROM emulation-friendly Flash. The architectural simplicity and deterministic instruction timing make the device well-suited to safety-conscious and interrupt-driven designs that demand predictable response.
Typical applications include remote keyless entry (RKE) transmitters, security sensors, automotive body electronics, industrial control logic, low-end appliance control, battery-powered sensor nodes, and KeeLoq-compatible encoders. The internal oscillator plus ICD reduce BOM and board area, while the KeeLoq module delivers secure rolling-code transmission in a single chip.
When designing with this device, note that the 4.5V to 5.5V supply range and 20 MHz clock limit low-voltage and high-throughput use cases. For 3.3V-only systems, consider the PIC16F636-I/SL (SOIC) variant or the lower-voltage PIC16F88x family. Place a 100 nF decoupling capacitor close to VDD, and tie MCLR through a pull-up if not driven by an external reset source.
Drop-in alternatives for PIC16F636-I/P — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with PIC16F636-I/P (same form factor and footprint) — differing in Operating Temperature, Package, RoHS Status, Analog Comparators, Core Architecture.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16F636-E/P
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$1.65 / Unit
View Datasheet →PIC16F636-I/ST
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$1.29 / Unit
View Datasheet →PIC16F630-I/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F676-I/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F636-I/P Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC (Harvard) |
| Program Memory Type | Flash |
| Program Memory Size | 3.5 KB (2K x 14 words) |
| RAM | 128 bytes |
| EEPROM | 256 bytes |
| Maximum CPU Frequency | 20 MHz |
| Supply Voltage Range | 4.5 V to 5.5 V |
| I/O Pins | 12 |
| Analog Comparators | 2 |
| Cryptographic Module | KeeLoq-compatible hardware encoder |
| Low-Voltage Detect | Programmable (PLVD) |
| ADC | None |
| Internal Oscillator | 8 MHz |
| In-Circuit Debug | Yes (ICD interface) |
| Package | 14-pin PDIP (DIP-14, 0.300 inch, through-hole) |
| Operating Temperature | -40 C to +85 C (Industrial) |
| Instruction Set | 35 single-word instructions |
| Brown-out Reset / Power-on Reset | Yes |
| Watchdog Timer | Yes (with dedicated on-chip RC oscillator) |
| RoHS Status | Compliant (lead-free) |
PIC16F636-I/P Pin Configuration
| Pin 1 | RA5/T1CKI/OSC1/CLKIN/PGM — I/O port A bit 5 / Timer1 clock / oscillator input / ICD data |
| Pin 2 | RA4/AN3/T1G/OSC2/CLKOUT — I/O port A bit 4 / analog input 3 / Timer1 gate / oscillator output / clock out |
| Pin 3 | RA3/MCLR/VPP — I/O port A bit 3 / Master Clear reset (active low) / programming voltage |
| Pin 4 | RA2/AN2/TOCKI/INT/COUT — I/O port A bit 2 / analog input 2 / Timer0 clock / external interrupt / comparator output |
| Pin 5 | RA1/AN1/C1IN-/ICSPCLK — I/O port A bit 1 / analog input 1 / comparator 1 inverting input / ICD clock |
| Pin 6 | RA0/AN0/C1IN+/ICSPDAT — I/O port A bit 0 / analog input 0 / comparator 1 non-inverting input / ICD data |
| Pin 7 | VSS — Ground reference |
| Pin 8 | RB7/ICCK/ICDCLK — I/O port B bit 7 / ICD clock |
| Pin 9 | RB6/ICDT/ICDDAT — I/O port B bit 6 / ICD data |
| Pin 10 | RB5 — I/O port B bit 5 |
| Pin 11 | RB4 — I/O port B bit 4 |
| Pin 12 | RC5 — I/O port C bit 5 |
| Pin 13 | RC4 — I/O port C bit 4 |
| Pin 14 | VDD — Positive supply voltage (4.5 V to 5.5 V) |
Typical Applications
PIC16F636-I/P is suitable for 7 applications: Remote Keyless Entry (RKE) Transmitters, Garage Door Openers and Gate Controls, Security and Alarm Sensor Nodes, Automotive Body Electronics, Low-End Appliance Control, Industrial Control Logic and Encoders, Battery-Powered Sensor and Meter Nodes.
Remote Keyless Entry (RKE) Transmitters
The PIC16F636-I/P fits remote keyless entry transmitters because its integrated KeeLoq-compatible Cryptographic Module performs rolling-code encryption in hardware, offloading the cipher from the CPU and enabling a 4.5 V to 5.5 V single-coin-cell or dual-coin-cell supply. At 20 MHz clock and 3.5 KB Flash, it can run a 4-button RKE encoder with bidirectional learn, secure transmission, and low-battery detection in a 14-pin PDIP package.
Recommended
Garage Door Openers and Gate Controls
The PIC16F636-I/P suits garage door openers and gate controls because it integrates KeeLoq rolling-code security, two comparators for safety-edge sensing, and PLVD for low-battery detection in a single 14-pin PDIP part. With 3.5 KB Flash and 128 bytes RAM, it can run multi-button transmitters with secure learn and proximity pairing; the internal 8 MHz oscillator reduces BOM to a single IC plus an RF transmitter.
Recommended
Security and Alarm Sensor Nodes
The PIC16F636-I/P fits PIR motion detectors, door/window sensors, and glass-break detectors because its low-voltage detect, internal 8 MHz oscillator, and 256 bytes EEPROM deliver tamper-resistant storage for alarm event logs in a 14-pin PDIP package. The two analog comparators can directly interface PIR sensors and reed switches, while 12 I/O pins drive LEDs, buzzers, and an RF link.
Recommended
Automotive Body Electronics
The PIC16F636-I/P works in automotive body controllers (interior lighting, seat-position encoders, accessory timers) thanks to its -40 C to +85 C industrial range, KeeLoq for secure key fob pairing, and 14-pin PDIP through-hole construction that supports hand-repair and prototype wiring harnesses. The 4.5 V to 5.5 V supply aligns with automotive 5 V rails, and 3.5 KB Flash stores lookup tables for seat-position or accessory logic.
Recommended
Low-End Appliance Control
The PIC16F636-I/P fits white-goods sub-modules (coffee machines, countertop ovens, blenders, fan controllers) because its 12 I/O pins drive relays, triacs, keypads, and 7-segment displays, while 3.5 KB Flash holds the state-machine control code. The PLVD module monitors supply sag during motor inrush, and the internal 8 MHz oscillator avoids external crystal cost.
Recommended
Industrial Control Logic and Encoders
The PIC16F636-I/P suits industrial encoders (rotary pulse generators, conveyor counters, machine-tool limit switches) because of its 20 MHz instruction rate, two analog comparators for quadrature decoding, and 256 bytes EEPROM that retains count presets across power cycles. The 14-pin PDIP form factor is friendly to retrofits and DIN-rail prototypes where hand-soldering remains common.
Recommended
Battery-Powered Sensor and Meter Nodes
The PIC16F636-I/P supports short-life battery sensor nodes (utility meters, irrigation valves, handheld instruments) where its 4.5 V to 5.5 V range accepts two lithium AA cells, internal 8 MHz oscillator eliminates external crystal drain, and PLVD generates an early low-battery warning. The two comparators can directly sense analog signals without an external op-amp, and 256 bytes EEPROM stores calibration constants across battery swaps.
Recommended
Recommended Products Summary
Engineering reference data for PIC16F636-I/P — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16F636-E/P | PIC16F636-I/ST | PIC16F630-I/P | PIC16F676-I/P |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 14-pin PDIP (0.300 inch) | 14-pin PDIP - same | 14-pin TSSOP - same pin count, SMD | 14-pin PDIP - same | 14-pin PDIP - same |
| Program Memory (Flash) | 3.5 KB (2K x 14) | 3.5 KB | 3.5 KB | 1.75 KB (-50%) | 3.5 KB |
| RAM | 128 bytes | 128 bytes | 128 bytes | 64 bytes (-50%) | 128 bytes |
| EEPROM | 256 bytes | 256 bytes | 256 bytes | 128 bytes (-50%) | 256 bytes |
| Maximum CPU Frequency | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| Supply Voltage Range | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 2.0 V to 5.5 V (wider) | 2.0 V to 5.5 V (wider) |
| KeeLoq Cryptographic Module | Yes (hardware) | Yes (hardware) | Yes (hardware) | No | Yes (hardware) |
| Analog Comparators | 2 | 2 | 2 | 2 | 2 |
| 10-bit ADC | No | No | No | No | Yes (8 channels, 10-bit) |
Key Differentiators
- Integrated KeeLoq-compatible hardware Cryptographic Module (vs PIC16F630-I/P)
- Doubled Flash program memory versus the PIC16F630 family (vs PIC16F630-I/P)
- Adds 10-bit ADC without changing pinout (vs PIC16F676-I/P)
Design Notes
Place a 100 nF ceramic decoupling capacitor as close as possible to the VDD pin (pin 14) and a 10 uF bulk capacitor at the board power entry. The PIC16F636-I/P operates from 4.5 V to 5.5 V; brown-out reset and power-on reset are enabled by configuration bits. Tie MCLR (pin 3) to VDD through a 10 kohm pull-up resistor unless an external reset supervisor drives it, and add a 100 nF cap from MCLR to ground for noise immunity.
When using the internal 8 MHz oscillator, leave OSC1/OSC2 (pins 1 and 2) as standard I/O or tie them per configuration. For crystal mode, route the crystal traces short and symmetric, with the crystal and load capacitors within 5 mm of the pins. Keep ICD lines PGD/PGC away from switching power traces; route the entire ICD interface connector footprint even if unused to keep in-circuit debugging available during development.
Do not exceed 5.5 V on VDD or apply reverse polarity; the PIC16F636 lacks internal reverse protection. The KeeLoq Cryptographic Module requires the manufacturer's Microchip KEELOQ library and proper configuration of security fuses, otherwise rolling-code transmission will be insecure. For 3.3 V-only designs, the PIC16F636-I/P is unsuitable - select PIC16F18313 or PIC16LF88 instead.
The ICD pins PGD (RA0) and PGC (RA1) are shared with analog comparator inputs; if you enable the comparator peripheral, ICD will not function until the comparator is disabled. Reserve RA0/RA1 for ICD during bring-up, then reassign them after code is locked. ICDCLK (RB7) and ICDDAT (RB6) share port B and must remain available for the debugger; do not load these pins with low-impedance peripherals during development.
Compliance Information
RoHS-compliant per DigiKey/Mouser listings. Not AEC-Q100 qualified; for AEC-Q100 automotive qualification use PIC16F636-E/P (extended temperature) or PIC16F88x automotive grade. Lead-free packaging confirmed by tube and tray packaging codes.
